"In the long run, [Firefox] will always be more secure [than Internet Explorer] because we have transparency and we have external contributors," Christopher Blizzard, a board member for the Mozilla Corporation, said during a session at the Red Hat Summit in Nashville.
Microsoft is set to release Internet Explorer 7 later this year, and the browser is expected to have dramatically improved security features.
Mozilla has been forced to fix numerous Firefox security flaws in recent months. The organisation released an update last Thursday that repaired 12 security vulnerabilities, five of which were rated 'critical'.
Such a rating indicates that an attacker could exploit the flaws to install software on a system without any user interaction.
Microsoft issued three security updates during its monthly patch release in May, none of which were related to the Internet Explorer browser.
"We do fix a lot of bugs, but we also have transparency. You're going to know everything that we fix," said Blizzard.
"Internet Explorer has known bugs that still haven't been fixed. We do regular security releases."
In addition to open source contributions, Blizzard also touted the Mozilla Security Bug Bounty Program that pays a $500 'finder's fee' to users who report valid critical security bugs.
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